systemd-cgls recursively shows the contents of the selected Linux control
group hierarchy in a tree. If arguments are specified, shows all member
processes of the specified control groups plus all their subgroups and their
members. The control groups may either be specified by their full file paths
or are assumed in the systemd control group hierarchy. If no argument is
specified and the current working directory is beneath the control group mount
point /sys/fs/cgroup, shows the contents of the control group the working
directory refers to. Otherwise, the full systemd control group hierarchy is
shown.